Answer:
This phenomenon is applying the principals of Gestalt Theory of Visual Perception.
Explanation:
This theory was proposed by the Gestalt group in Germany, in the early 1920's. The Gestalt group, was the first research group to sistematically study visual perception and organisation.
The theory of visual perception is composed of six principles that aim to explain phenomenons such as the one described in the question, why a series of dots arranged in the shape of a face is perceived as a face and not a series of dots. The principles are: proximity, similarity, common fate, good continuation, closure and area and simmetry.
